Hydrogen-Bonded Ion-Ion Interactions in a Molten Salt Precursor: The Crystal Structure of 1-Methyl-3-Ethylimidazolium Chloride

摘要

The crystal structure analysis of the molten salt precursor, 1 -methyl-3-ethylimidazolium chloride (MEIC1), was undertaken as part of an investigation of the ion ion interactions in room temperature melts, where mole fraction N of A1C13 is less than 0.5. These melts are of interest as electrolytes in high energy density batteries, as solvents for studying ionic complexes, and as catalytic solvents for organic reactions. Hygroscopic crystals of MEIC1 were grown in acetonitrile and sealed under helium gas in a capillary tube. The orthorhombic space group is P212121, with a = 10.087 (1), b = 11.179(1), c = 28.733(4) A, V = 3240.0 A3 mol. wt. = 146.62, D calc = 1.204 g/cc for Z = 16. The asymmetric unit contains four MEI+...C1 ion pairs. The MEI+ ions cluster in four distinct layers perpendicular to the c-axis. Similarly, the arrangement of C1- ions is a layered one. Each C1- interacts with three MEI+ ions and each MEI+ is associated with three nearest C1- ions. The distance of C1- from a ring carbon atom averages 3.55 A. Molten salt, Imidazolium chloride, Battery, Electrolyte, Hydrogen bonding, Imidazoles, Chlorides. (mjm)